EP3023916A1 - Encoding/decoding of information from a graphical information unit - Google Patents

Abstract

The invention relates to a method for coding information into a graphic information unit (1), characterized by the steps: - Determining an outer contour (2) of the information unit (1); and - Coding information by means of at least two-dimensional code (10) in at least one area (3) exclusively within the outer contour (2), wherein the coding on pixels (11 a, 11 b) of the information unit (1) is applied.

Description

The invention relates to a method for coding information from a graphic information unit and to a method for decoding information from a coded graphic information unit.

Beginning with logistics, many services, commerce, goods and personal identification, and manufacturing companies, automatic identification (Auto-ID) using bar code technologies has become very important in recent years. The purpose and purpose of the Auto-ID is the provision of digital information on persons, animals, goods and goods.

In addition to automatic identification, so-called mobile tagging offers a large area of application for new barcode techniques. Mobile tagging distinguishes three different areas: commercial tagging, such as additional information on products, direct downloads, direct forwarding to the website of a company. Public tagging enriches existing public information such as signs, directions, timetables, sights, and the like. Finally, private tagging, where the focus is on the transmission of private information such as for business cards, URL links, etc.

The development and spread of mobile devices, printers, cameras, scanners and the associated increasing mobile possibilities in the integration of barcodes as a digital information medium in everyday life was a rapid growth of applications for barcodes. In particular, the QR (Quick Response) code is increasingly being integrated with mobile tagging into everyday life with a growing trend. The reasons for the rapid dissemination of the QR code are largely due to its high information density (up to 4296 characters) with a small footprint and the relatively high reading reliability (integration of algorithms for error correction and error integrity testing) with modern cameras. Another important aspect of the high level of awareness of the QR code is the free provision or integration of the QR code into existing barcode scanner software, which can be used on all common smartphones and tablets.

The development of the common barcodes used today in other sectors of the economy (including the QR code) was carried out under the main consideration of the logistics industry as a field of application. This focus is reflected above all in the design and security mechanisms. Especially for the marketing area and the enrichment of existing public information, the original black and white matrix pattern is not sufficient from a graphical and promotional point of view.

Another criticism of the currently used barcodes is the very low customizability, so that an individual corporate design is not feasible. For this reason, graphic extensions have been used e.g. on the QR code (Customized QR Code) made possible by the high data redundancy of the QR code. Despite a maximum possible data redundancy of 30% in the Customized QR code, a code that is not adapted to the additional visual information and that can not be interpreted by humans and is detached from the rest of the graphic context dominates the overall picture.

Another major disadvantage of most existing barcode solutions (including the QR code) is the implementation of security conditions. For the user, there is no security concept for all current mobile tagging barcode solutions which can be read by a smartphone, since it is not possible to detect what causes the scanning before reading. This weakness has already been exploited by installing malware on the smartphone or by redirecting to paid services. Another major weakness of many barcodes is the potential for falsification by third parties, which in turn can lead to user harm (e.g., replacement of product labels).

US 8,144,922 B2 discloses the use of a transparent infrared-absorbing ink for coding.

US 8,526,670 B2 discloses overlaying a logo with a grid of cell dots having a brightness that is higher than the brightness of the logo.

EP 2 224 373 A2 discloses that lighter dots are superimposed on a logo. It is essentially provided that the information is displayed by means of white cell dots, which are superimposed on a black logo.

EP 2 731 057 A1 discloses a method of encoding information into an image by overlaying a visible raster across the image and encoding information in the raster. The coding can be arranged above the surface or next to the surface of the image.

The invention is based on the object of improving the coding or decoding of information.

This object is achieved with a method for coding according to claim 1 or a method for decoding according to claim 13.

• Bestimmen einer Außenkontur der Informationseinheit; und
• Codieren von Information mittels eines mindestens zweidimensionalen Codes in mindestens einen Bereich ausschließlich innerhalb der Außenkontur, wobei die Codierung auf Bildpunkte der Informationseinheit angewendet wird.

The method according to the invention for coding information into a graphical information unit comprises the steps:

• Determining an outer contour of the information unit; and
• Coding information by means of at least two-dimensional code in at least one area exclusively within the outer contour, wherein the coding is applied to pixels of the information unit.

The inventive method has the advantage that a novel and more intuitive way of interaction between analog real information, such as logos and symbolic representations in print media or on real signs or stickers in everyday life, and the digital world is possible. This is made possible by the fact that the code is integrated into the information or that the code is applied to the information unit. So far, the original image information and the code were always separated. The code is applied only within the area of the information unit, so that individual pixels, pixels or sub-elements of the information unit are changed or coded. By restricting the code application to the information unit, the appearance of the information unit remains largely intact.

A graphic information unit comprises here first any graphical representation. This can include single or linked symbols such as letters and numbers, logos and / or images. The outer contour corresponds to a limitation or delimitation of the information unit from a background. The two-dimensional code has two coordinates, for example x and y, where the coordinate system can be defined or specified by the surface on which the information unit is arranged and / or by the information unit itself. This 2D encoding can be implemented as a black and white code. The code or the coded information unit can be attached to physical locations and objects and distributed digitally and ensures a contentual reference in visual form of the information to be coded. In contrast to the barcode forms currently used in practice, such as the QR code, the content to be displayed is directly interpretable for humans and for a capture device such as a scanner. The coded information has a much more realistic appearance. These design-technical measures are of particular importance, particularly with regard to the human-computer interaction, since a realistic understanding of digital content results in a better understanding of the digital content of the barcode and everyday use appears more intuitive. In addition, these measures increase the user's confidence in scanning the encoded information unit. In the field of logistics, a further advantage would arise from the combination of the product image with the associated code information, since this would result in a lower error rate when assigning the code to the appropriate product when delivering new goods.

A three-dimensional color coding can be used, wherein a color space of the color code is at least a part of a color space of the information unit. In this case, the adaptation of the colors to be used to the information unit to be coded is also understood to be realistic, so that the coding of the code with a variable number of color tones can be carried out. By adapting to the color space of the information unit in addition to the shape and the color design of the information unit and thus their recognition value remain largely.

A sub-color space of the color space of the color code may be locally determined for a contiguous group of elements of the adaptive raster, depending on a so-called group color associated with that group of raster elements. This group color is determined locally and separately for that area of the information unit in which the group of elements of the adaptive grid is arranged. In the simplest case that this area of the information unit is monochrome, the group color corresponds to the color of the area. If the area has a color gradient or is generally multicolored, then the group color can be determined as the mean or mode of the color values present in the area. A contiguous group of elements of the adaptive grid is formed in particular by elements arranged in adjacent rows and / or columns of the grid, for example by elements of the grid which form an n * m sub-matrix of the grid, where n and m represent integers. Such a specific one In this case, the sub-color space for a contiguous group of elements is basically independent of a sub-color space which is determined for a further group of elements of the raster which are arranged in a different area of the information unit. In this way, the entire color space of the coding is first formed by the individual locally calculated partial color spaces.

Each of the colors of such a sub-color space may differ from the corresponding group color-and any other color of the sub-color space-only with respect to at least one predetermined color parameter (such as brightness, saturation, hue). A distinction according to the brightness is preferred. The colors of the sub-color space are thus all sufficiently similar or matching the group color, which in turn represents the color of the underlying area of the information unit. In this way, an encoding of the information unit is possible, which disturbs the visual impression of the information unit only very slightly. According to a first variant, all the colors of the sub-color space may deviate "in one direction" along the color parameter from the group color, for example all colors of the sub-color space may be lighter than the group color. This facilitates decoding. Alternatively, the colors of the sub-color space in "different directions" along the color parameter may differ from the group color, for example, be lighter or darker than the group color. In this way, an optically even less conspicuous coding is obtained.

Because the partial color spaces are determined locally, merely with reference to a contiguous group of elements of the grid, in a corresponding decoding step, when decoding the information encoded by the group's raster elements, only the colors of the partial color space assigned to the group must also be used get noticed. This simplifies decoding as compared to a coding method which uses a global color space for coding. On the other hand, the entire color space of the coding, which can be understood as a combination of the partial color spaces described, can be so large that the coding can be color-matched in an optimum manner to the graphic information unit.

In order to simplify the decoding associated with color coding formed in the manner described above, a given element of the group of adaptive raster elements may be colored with that color of the sub-color space that is different from the other colors of the sub-color space of the given color parameter most clearly different, for example, as the brightest color of the sub-color space. This color then forms a first reference color. In the case that For example, the group color is clearly recognizable even in the step of decoding, since the corresponding area of the information unit is, for example, monochrome, the group color can serve as the second reference color. The colors of the sub-color space other than the first reference color are then arranged with respect to the color parameter "between" the first reference color and the second reference color. Alternatively, as the first and second reference colors, the two colors of the sub-color space can be selected which differ most clearly from one another with respect to the given color parameter, but also from the group color. For example, this may be the brightest and the darkest color of the sub-color space, for example, in the case that the group color is arranged with respect to the brightness between these two colors. A first predetermined element of the group of elements of the adaptive raster may then be colored with the first reference color, and a second predetermined element of the group of elements of the adaptive raster may be colored with the second reference color. In the step of decoding, the two reference colors can then be read out first and, based on their knowledge, a predetermined number of colors of the sub-color space, the remaining colors of the sub-color space can be determined. In other words, according to this embodiment, each of the contiguous groups of raster elements has its local color table. Basically, any two colors of the sub-color space can be used as reference colors of the sub-color space, ie it is not necessary for the colors of the most varied colors to serve as reference colors. According to such a variant, in addition to the number of colors of the sub-color space, it is then necessary to specify in decoding, for example in header information, how the remaining colors of the sub-color space are arranged relative to the reference colors in the sub-color space with respect to the color parameter.

The coding can have at least two markings for position detection of the information unit. On the one hand, markers for position detection can be used to clearly indicate the bearings of the coded information unit relative to a detection device during decoding. Alternatively or additionally, markers for position detection can serve to specify limits of a portion of a grid used for information coding. Preferably, for each of these two purposes (detection of the relative position to the detection device, recognition of the boundaries) separate, mutually distinguishable markings are used for position detection. The ability to detect position increases the speed of detection of the code, since with the at least two markers a recognition grid or pattern can be placed directly on a coding grid. In particular, for an offline decoding, that is without a central server, the location detection is important.

As markers for position detection optically conspicuous and automatically, by image recognition, easily identifiable markers can be used, as they are known for example from the QR code.

Alternatively, e.g. in the case where, as described in detail above, a three-dimensional color coding is used and an adaptive raster is used for the encoding, markers for position detection - alone or among others - by suitable coloring of at least one element of the adaptive raster with at least one specific one Marking color can be formed. The marking color or the marking colors, which characterize one or more raster elements as a position marker or part of a position marker, each exceed a predetermined color difference to a color of a region of the information unit in which the at least one element is arranged. A raster element is in each case dyed with one of the marking colors. In the case where a plurality of raster elements are colored with one of the marker colors to form a position marker, one or more marker colors may be used for this, but always only one of the marker colors for one of the raster elements. In this way, the mark remains visually inconspicuous compared to conventionally known position markings.

A mark for position detection, which is formed by coloring a plurality of elements of the adaptive grid with one or more of the marking colors, can additionally be identified by the elements of the plurality of elements having a predetermined positional relationship with respect to the adaptive grid. In other words, here color information and relative position information play together to form a marker for position detection.

The coding can have a header with information about the coding. In this header information may be included, which may make possible or simplify a decoding under certain circumstances. The header may include information such as an indication of a decoding library (version), a color coding table, redundancy information, the character set to be used, and encryption information.

The information to be encoded can be encoded before encoding. This integration of a security mechanism enhances security by protecting the encoded information unit from tampering by third parties and by protecting the user from downloading malware or forwarding to paid services without consent.

For the coding, an adaptive grid can be used, which is adapted to the outer contour and / or the color space of the information unit. The dynamic or adaptive grid allows optimal adaptation of the grid and thus the coding to the information unit, so that the information unit is only slightly changed, so that a human observer of the overall impression is maintained, a machine detection unit, the code is accessible. It is advantageous if the human observer recognizes the coding, so that he can, for example, direct his smartphone to the coded information unit in order to obtain the coded information.

• Erfassen einer mit einem Verfahren nach mindestens einem der Ansprüche 1 bis 12 codierten Informationseinheit; und
• Decodieren der Information aus der codierten Informationseinheit.

The inventive method for decoding information from a coded graphic information unit comprises the steps:

• Detecting an information unit encoded by a method according to at least one of claims 1 to 12; and
• Decoding the information from the encoded information unit.

Detecting includes, for example, recording and / or scanning with a detection unit, such as a smartphone, tablet, or a dedicated scanner unit, such as those used in logistics. The decoding can be done with the detection unit and / or an associated computer unit such as a server. For a smartphone, this can preferably be done by an application or app.

A detection device can transmit the information to a database and receive information associated with the information from the database. This so-called online decoding usually works with a coded link pointing to an entry in the database. For this, the scanner is connected to the database.

A detection device can process the information. In this offline decoding, all the information is contained in the coded information unit, so that no online functionality must be present in the recording device.

• Anpassen und/oder Anwenden eines Rasters auf die erfasste, codierte Informationseinheit;
• Erkennen einer Orientierung der erfassten, codierten Informationseinheit anhand mindestens zwei Markierungen;
• Erfassen eines Headers;
• Decodieren der Information basierend auf Angaben des Headers;
• Durchführen einer Fehlerkorrektur;
• Entschlüsseln der Information;
• Anzeigen der Information.

During decoding, at least one of the following steps can be performed:

• Adapting and / or applying a raster to the acquired coded information unit;
• Recognizing an orientation of the detected coded information unit based on at least two markings;
• Capturing a header;
• Decoding the information based on indications of the header;
• Performing an error correction;
• Decrypting the information;
• Display the information.

These steps or some of these steps may be performed during decoding. The above sequence is not mandatory, the steps can also be executed in a different order or partially in parallel.

A computer program product according to the invention comprises program parts which, when loaded in a computer, are designed to carry out a method as described above. The same advantages and modifications apply as described above.

Figur 1

eine schematische Darstellung einer Informationseinheit und einer codierten Informationseinheit;

Figur 2

eine schematische Darstellung der Codierung einer Informationseinheit;

Figur 3

eine schematische Darstellung der Decodierung einer codierten Informationseinheit,

Figuren 4 bis 9

schematisch spezifische Schritte eines Verfahrens zum Codieren von Informationen in eine graphische Informationseinheit gemäß einer ersten bevorzugten Ausführungsform;

Figur 10

eine entsprechend codierte Informationseinheit; und

Figur 11

eine Variante der Informationseinheit aus Figur 10.

The invention will be explained below in embodiments with reference to the accompanying drawings. Show it:

FIG. 1

a schematic representation of an information unit and a coded information unit;

FIG. 2

a schematic representation of the coding of an information unit;

FIG. 3

a schematic representation of the decoding of a coded information unit,

FIGS. 4 to 9

schematically specific steps of a method for encoding information in a graphic information unit according to a first preferred embodiment;

FIG. 10

a correspondingly coded information unit; and

FIG. 11

a variant of the information unit FIG. 10 ,

In FIG. 1a an information unit 1 is shown. The information unit 1 consists here of a logo or a pictorial representation. In general, an information unit may comprise all graphical representations or two-dimensional images. The two dimensions are the two dimensions of the surface on which the information unit is mapped. The surface may be flat, such as a sheet of paper or a poster. On the other hand, the surface may be curved, such as in an advertising medium. The two coordinates or dimensions can be referred to as x and y direction.

The information unit may also consist of one or more symbols such as letters or numbers, or a combination of one or more symbols with one or more pictorial representations.

The information unit 1 is bounded by an outer contour 2. That is, the outer contour 2 is the boundary between the information unit 1 and a background. The background can lie on the same surface or be arranged on another surface or surface.

The outer contour 2 surrounds an inner space 3, that is to say a region exclusively within the outer contour 2. The inner space 3 may comprise a plurality of regions or sections, of which one region 4 is shown by way of example. The areas may be defined, for example, by different colors or color spaces. On the other hand, the areas may be defined by different contents, such as a symbol and a pictorial representation. For example, in the illustrated example of a home, the right side wall is area 4. The side wall may have a different color than the roof and the base of the house. Also, the columns at the front of the house can be considered as an area, wherein the three-dimensional effect of the columns is caused by different white or gray tones.

The information unit 1 can be, for example, a logo for a company, an institution, a service or a product. It can also be an indication of information or application. The information unit usually transports a content with which the viewer of the information unit 1 connects or awaits something. In the classical sense, such a logo is used to link ideas with a company and / or its product.

In addition to the functions of marketing and the information exchange, for example in public space, such information units are also used in the field of logistics in order to identify goods, packaging and / or transport containers and to permit fast and secure allocation or information.

In order to further develop such information units 1, that is to provide them with extended functionality or increased information density, an encoding of the original information unit 1 is made FIG. 1a in an encoded information unit 5 according to FIG. 1 b proposed.

In this case, information or user data are integrated by applying an at least two-dimensional code within the outer contour 2 to pixels of the information unit 1. The outer contour 2 and thus the outer shape thus remain. The coding can also be applied to the outer contour 2. The coding takes into account the external appearance of the original information unit 1. This is done via the retained outer contour 2. The outer contour 2 is preferably identical to the original information unit 1 and the coded information unit 5. On the other hand, color values or gray levels of the information unit can be taken into account in the coding, so that the overall impression of the original information unit also after Coding is preserved.

In FIG. 1b are exemplified the two areas 3 and 4 coded. It is possible to code all, one or as shown, several subregions or parts of the information unit. The code 10 consists of individual pixels 11, of which two pixels 11 a and 11 b are exemplified. To the pixels 11 in the representation of FIG. 1b To better represent each pixel 11 is assigned a pattern. Each pattern or transition between two preferably adjacent patterns may stand for one bit in a black-and-white coding or for a value of one or more bits in a colored coding.

For illustrative purposes in the black-and-white representation of the figure, the pixels 11 are each shown as a pattern. This representation is preferably a placeholder for a gray value or color value scale, which can not be represented in the figure, which corresponds to the original representation or original color or colors of the original information unit 1 FIG. 1a is adjusted.

By means of this coding adapted to the information unit, the overall impression or the aesthetic impression also remains completely or at least almost completely preserved even after the coding for the human observer. In addition, however, the information unit additionally contains the coded function. Thus, the information unit now has the dual function of transporting the original information as well as the additional coded information. The encoded information, or the presence of encoded information, or in other words the application of a code to the information unit, may be visible to the human observer so as to provide an indication of the additional encoded information.

Based on FIG. 2 Now the process of coding will be described in more detail.

In a first step or block 100, the information unit is determined or determined. This comprises, first of all, the selection for example of at least one symbol and / or at least one image unit. Next, the outer contour 2 of the information unit is determined. This can be realized by manual and / or automated techniques such as cropping or cropping.

In a further step 110, the information or user data to be coded is input. The information may include, for example, text that already exists or is created on a computer. The text may include numbers and / or letters and, for example, provide information about the entity or related companies or the like. The information may also include or be a program code or instruction to a program. This may, for example, include or be a link for an Internet address or a database entry.

In step 120, the payload or information is preprocessed. The preprocessing may include, for example, compression of the information and / or selection of the code. In order to improve the information density to be coded, the information to be coded can be converted into codewords or compressed in a preprocessing step. For this purpose, corresponding existing compression methods can be used and adapted if necessary. In particular, methods from the field of lossless text compression are considered, such as the LZW algorithm, the Huffman coding or the arithmetic coding.

In a next step 130, the information to be encoded into the information unit 1 is encrypted.

As a result of the ever increasing proliferation of mobile Internet-enabled devices in the private and commercial sectors, the number of criminal attacks on the owners of these devices is correspondingly increasing. The so-called mobile threats may include, inter alia, spying on information, loss of information, identity theft and / or installing malicious software. Particularly in the field of mobile tagging, these vulnerabilities are often a negative point for existing barcode solutions, such as the QR code, since prior to scanning the barcode, no advance information is visible to the user and the barcode scanners are not checked for decoding Information takes place.

Since the coding rules of all currently known barcode solutions are open to implementation, manipulation of the coded information by the exchange of the barcode by third parties is possible. To avoid these vulnerabilities, uses of appropriate security mechanisms will take place.

The coding can be implemented with two different approaches, so that the coding or the code is variably adaptable to a wide variety of applications. On the one hand, coding of the entire information can take place directly in the barcode and, on the other hand, storage of all the information within a database and exclusive coding of the database reference can be provided directly in the information unit.

This first approach of coding the entire information directly in the code is particularly found in the field of mobile tagging, in that, among other things, URLs or contact information are coded directly in the barcode. Since all the information is coded directly in the barcode, this approach allows a much lower information density compared to use with a database. After printing the code, no subsequent changes can be made to the stored information. Then, a subsequent or dynamic change of the information to be encoded, for example, typing errors or no longer existing URL addresses is required.

This second approach of storing all the information within a database and encoding the database reference is most often selected within the logistics industry and in many applications of Auto-ID systems. For identification and labeling, among other things, counting the products, a database is needed. The code is used in these cases only for the identification of the product and the associated information is stored in a database.

In order to enable transmission of the data of the decoding, for example, when decoding on the smartphone to the respective software for managing the database entries, the smartphone application includes a communication option such as a TCP / IP functionality. Furthermore, there is a server component which receives the decoded data on the server and has an interface for data exchange with the software used for managing the database entries. Thus, the decoding of the database reference takes place on the client, such as a smartphone. Then the Data is sent to a central server, which accordingly returns the appropriate information from the database to the client for display or further processing. The implementation of this infrastructure can use the identical decoding functionality as in the first approach and can therefore be seen as an extension of the first approach to a TCP / IP transmission component.

For protection against manipulation by third parties already existing encryption methods or digital signature methods within the coding or decoding process and / or a check digit calculation method can be used. This prevents or impedes manipulation of the proposed code. By means of the signature method used and / or the check digit calculation method, it can be recognized whether the original picture or the information unit has subsequently been changed and is thus no longer trustworthy. To protect the user from downloading malware or forwarding to paid services without consent on the one hand control mechanisms in the smartphone application and on the other hand a non-open encoding provided. Within the smartphone application, defective abnormalities in the decoded information can be filtered and displayed to the user.

In a further step 140, the information or user data is now encoded. For this purpose, first a grid is placed over the information unit 1. The grid is not independent or separate from the information unit. First, it is applied only within the outer contour 2, and secondly, it is not visible, but provides a framework for the application of coding from individual raster elements or pixels of the information unit 1. The raster is effectively a template by which the encoding is applied to the information unit 1.

The selection of the grid structure is determined by the raster shape or raster expression and an essential parameter for the later code, since the raster shape and the raster color influence the design of the image to be encoded. In addition, the reading reliability of the code and the possible information density also depend on the choice of raster form or color.

For encoding the useful characters such as letters, numbers and / or characters within the code, the binary system is preferably used. Accordingly, gray scale changes or color changes between the individual raster elements or pixels of the information unit or of the image are converted into bit sequences. To convert the bit sequences into useful characters, a reference table and a corresponding character set must be agreed. The reference table specifies the association between the existing bit sequence and the corresponding character from the selected character set. Preferably, common character sets such as the numeric, alphanumeric or the ISO character set are considered for the coding rules.

To improve a realistic representation and to increase the information density, a color coding is preferably used in addition to the 2-dimensional position coding, so that a three-dimensional code results. While a black-and-white code has an information density of one bit per pixel, a color code results in an information density of the number of colors per pixel. Since the color space is variable as a function of the information unit, the coding and its information density are also variable.

Due to the condition for realistic representation, the colors suitable for the coding image are preferably used for the coding. To determine the color space to be used, taking into account the colors of the original image, methods of image processing are used. In order to allow a variable number of colors to be used for encoding, the corresponding font reference table is also variable. Because the number of selected color tones for coding, the expression of the font reference table and the size determine the information density, a corresponding dynamic method is used. The dynamic method used is based on the given color space, which can be selected automatically on the basis of the image template or manually by the user. The assignment of the colors to the individual elements of the coding grid is calculated on the basis of the color differences at the position of this element in the original image. If the corresponding color difference is below the minimum limit that a camera needs, taking into account environmental influences (lighting, contamination, etc.), to recognize these colors as different colors, given a fault tolerance, the color differences are adjusted accordingly. The number of shades used to select the appropriate character set reference table is encoded directly in the code header.

Finally, in a final step 150 of coding, the design of the encoded data is adapted to the information unit. This task includes adapting the code pattern to the image, logo or symbolic representation of the information unit to be coded. In order to be able to code exclusively the logo or the symbolic representation and not the background of the original image, an automatic or semiautomatic separation of the logo or the symbolic representation from the background must take place before the coding. The exclusive use of the logo or the symbolic representation for coding is desirable for reasons of a realistic representation. Separation can be done manually by the user or by image processing techniques. Based on this separated image detail, which serves as an information unit in the course of the coding, a recognition pattern including a header, a coding grid and a variable position recognition for the coding is then automatically or semi-automatically determined.

Due to the very large variety of information units to be encoded or images, logos or symbolic representations in which the code is integrated, taking into account a high read security by conventional smartphones, tablets or commercially used monochrome or non-monochrome camera scanner on the form customizable code provided on the original image. For a variable position detection and an adaptable to the shape of the original image grid construction is provided.

After these steps, a coded information unit 5 has emerged into which additional information has been coded. In this case, the overall impression of the original information unit 1 has been preserved, because the coding is applied, on the one hand, only within the limits of the information unit and, on the other hand, directly to the information unit itself or to raster elements or picture elements of the information unit. Thus, a grid is used only as a mask or intermediate step of the coding, but is no longer in the coded information unit in full or directly no longer fully perceptible.

Based on FIG. 3 The decoding of a coded information unit 5 will now be described by way of example.

First, the coded information unit 5 is scanned or recorded. This can be done, for example, with a smartphone 6, a scanner 7 or a tablet 8. In general, an image acquisition unit, for example, in the form of a camera and an evaluation or processing unit is necessary, which evaluates the captured image, that is, extracts the coded information.

For this purpose, first in a step 200, the user data or the information is decoded. The step of decoding 200 comprises several substeps.

In order to correctly project the defined raster, which may be contained in the decoding library, onto the information unit 5, the relational position of the camera is determined to be the information unit 5, which is realized by one or more marks, preferably two or three, for position recognition. The pattern for position detection is selected so that an omnidirectional readability with a smartphone, tablet or a camera scanner is possible and yet the design of the original image is not negatively or only insignificantly influenced.

Depending on the field of application, different requirements are placed on the level of information density and the security of the code. While mobile tagging usually only requires shorter information to be stored in the code, such as digital business cards or URLs, higher demands are placed on the code in the area of logistics and Auto-ID systems. In addition to high security requirements, the code is in most cases linked to a database entry by the associated detailed article information is stored. In this case, the barcode not only serves to display information, but is also used for administrative tasks. For example, when the article is sold, the quantity in the corresponding database entry is reduced.

In order to meet the stated requirements for the code, an extension of the pure decoding functionality is provided by a TCP / IP component within the smartphone application. With this extension, a practical implementation of the following in practice the most frequently encountered infrastructure approaches for the processing and interpretation of barcodes is possible.

The first commonly used approach to decoding uses a database in which decoded code information is transferred from a client, such as a smartphone, to a central server, which returns information associated with the code through a database query. This can be a reading of a barcode from an article and a direct display of the corresponding article information. When used Server is both an in-house and a web server conceivable, so that depending on the security requirements and field of application, a variability in the infrastructure is possible. Even subsequent changes to the barcode, for example, typos or changing article information can be implemented with this solution, since in the code only the database reference is stored and therefore only a central database entry must be changed, rather than all barcodes affected by this change of information to re-encode ,

On the contrary, the decentralized local decoding approach exists on the terminal, such as a tablet or smartphone, which need not be connected to a network or server. This approach does not allow for any subsequent changes in the coded information and obtains the complete information solely from the image data. This approach is currently used in almost all mobile tagging applications and offers a high level of flexibility as there is no access to a network.

Depending on the area of application, the two approaches have advantages and disadvantages and are therefore selected on a case-by-case basis. To implement the two approaches, the same decoding functionality is used. By an optional, optionally by the later user, addable TCP / IP component for transmitting the decoded information to any server then the above approaches can be used in a variety of applications.

Based on the header, the position detection and the known decoding algorithm, the information unit is decoded. The information needed for decoding, such as the encoding version used, can be extracted or derived from the header or general information or agreement.

Based on the bit information from the individual picture elements or pixels or the bit information from the transitions between the individual picture elements or pixels, the decoding algorithm calculates the useful data. By using more than two colors, bit information of more than one bit per transition between two pixels is possible. When using two colors (eg black-and-white), encoding of one bit (0 or 1) per transition would be possible. The corresponding number of bit information per transition is therefore dependent on the number of colors for encoding. The stringing of successive bit information is called a bit sequence.

Using the character set reference table specified in the header of the encoded information unit, the bit string can be converted to the target alphabet or string using the character set reference table (eg, ASCII record - using an 8-bit string to represent one character of a character set of 256 characters) be transferred.

In a further, optional step 210, error detection or error correction is carried out. The data obtained from the error correction can optionally be used as empirical values or parameters for new codings in order to reduce the error rate during the transmission. Thus, a feedback loop to improve the coding / decoding arise. The error detection can be based on known methods, for example using redundancies or checksums.

Overall, the entire optical / imaging path is to be considered in the context of the efficiently usable code, and when parameter boundaries are reached, the code and / or the coding may once again have an effect. With regard to the code, the following parameters are defined, such as a minimally tolerable contrast, the influence of disturbances due to dirt, wear, damage, the maximum amount of information to be stored and the use of hierarchical information storage.

The code should also be usable by systems that have conventional fixed focal length cameras, such as smartphones. The image pickup path is characterized by the distance of the object to the recording system, the illumination of the object, the lens of the recording system with parameters such as focal length, image quality and light intensity. Another criterion is the sensor and the data storage, as well as parameters such as sensor size (resolution), signal-to-noise ratio, image data to be stored, the storage format, possibly lossy storage and additional information on the code information, such as location, time, etc ,

It makes sense in the usage concept of the code to enable information feedback during image acquisition. This feedback may include control of data acquisition, for example, detection of the coding type, analysis of the orientation, and control of the recording distance, with instructions given to the recording device by the recording algorithm. Other aspects may include image preprocessing as well as obtaining the destination information.

The individual components described above interact and are advantageously considered together. It is expected that development recursions will have to be made in order to create and implement a stable concept with high fault tolerance and a simple, real-time algorithm.

The consideration and the indication of fault tolerances are very important for the practical use, in order to enable a reconstruction of the information of faulty codes. Errors within a code can be caused by damage to the code, poor print quality, or interference due to environmental influences during recording. This can be caused, for example, by masking of the code by another object or unfavorable lighting conditions. Such errors must be taken into account for practical use in order to guarantee a high fault tolerance.

To account for error tolerances, existing error correction algorithms such as the Reed-Solomon algorithm can be used.

An element in the use of the code can be a redundancy of information to be integrated, in order to be able to reliably detect even severely disturbed data fields. Here, the implementable degree of redundancy plays the central role, since this has a direct influence on the still permissible disturbance of the code, for example by decreasing contrast, by missing or non-decodable area proportions and / or by the quality of the illumination. Parameters of the required image capture hardware, such as the sharpness of the image, the necessary effective image resolution and / or the speed of preprocessing or processing the image data also play a role.

The required algorithm or the performance of the image processing, such as the integration into the target environment / hardware, the real-time capability in the target environment and / or the ease of operation can also be taken into account.

The actual image processing involves the acquisition and extraction of the information of the code by means of the available surrounding hardware and its interfaces. In this case, it is necessary to separate the recognition algorithm and supplementary image processing tools in the sense of preprocessing, such as the acquisition of a pattern, the management of the hardware via a user interface during the creation of the image, such as the adjustment of the image Distance of the camera to the object, the detection and correction of a better recording angle, and / or the use of a hierarchical code, such as the parameters orientation, code type, basic information and / or detail information. Finally, the actual extraction of the destination information, that is the user data, is taken into account.

In step 220, the payload is decrypted when the encryption has been performed. This step is therefore optional. Information about the selected encryption may be included in the header, for example.

Finally, the payload data is displayed and / or processed. This can be done in the capture device such as the smartphone 6 or in another instance such as a computer connected to the capture device. Thus, the coded in the information unit and possibly encrypted information is available again.

With reference to the FIGS. 4 to 9 In the following, a preferred embodiment of a method for coding information into a graphical information unit will be described by way of example. In particular, the above with reference to Fig. 2 generally described steps 140 and 150, which relate to the coding of the information unit, explained in detail.

Fig. 4 shows a graphical information unit 301 with an outer contour 302, which defines and encloses an inner region 303 to be coded. The information unit 301 may be part of a logo, for example.

In a preparatory step, a grid adapted to the outer contour 302 is placed on the information unit 301 to code the information unit 301. The corresponding elements 320 of the adaptive grid are regularly arranged along lines and columns along predetermined directions (X and Y directions). The size and shape of the raster elements 320 as well as a grid spacing in each of the two directions, and thus also a number of raster elements, can be varied.

Fig. 5 illustrates, by way of example, an optional step of arranging markers 330, 340 which permit position detection of the encoded information unit during decoding.

The position detection markers 330 are arranged in order to be able to unambiguously determine a position of the encoded information unit relative to a detection device during decoding. That is to say, a detected coding of the information unit 301 can optionally be rotated and / or scaled on the basis of the markers 330, in order to enable unambiguous and correct decoding. A perspective distortion, which can occur when the coding is detected, can also be corrected by means of these markings 330. In the Fig. 5 By way of example, markers shown by way of example can be recognized and processed simply and without additional preparation after detection of the coding during decoding, thereby simplifying decoding as a whole.

Optionally, header information 332 may be incorporated into the coded information unit, which may include information or information that simplifies or makes possible the decoding of a coded information unit. Such indications may relate, for example, to the grid, a predetermined number of color gradations, an optionally used encryption and the like. Preferably, such header information is indicated by the dotted lines in FIG Fig. 5 indicated areas between the location marks 330 arranged so that it can be found quickly and easily at the beginning of the decoding process.

Further optionally additionally markings 340 may be provided for position detection, which define the boundaries of the grid used for the information coding. These limits are in Fig. 5 indicated by the frame 342.

In the FIGS. 6 to 9 It is shown how a concrete embodiment of a three-dimensional color coding can be formed. Different colors are represented in the figures by means of hatched areas.

As in Fig. 6 In a first partial step, the elements of the grid are respectively divided into groups 350 of contiguous elements 320 of the grid. In the example shown, such a group 350 consists of a 2 * 2 subgrid. It is understood that the dimension of such a sub-grid can be variable, for example, the size of 2 * 3, 4 * 2, 3 * 3, 4 * 4 or similar sizes may have. All that is essential is that all the elements of such a group are arranged in a contiguous region of the information unit, ie in a certain way adjacent to one another.

In a further sub-step, a group color 360 is now determined for such a group 350. This group color 360 is determined on the basis of a color distribution in the area of the information unit that comprises the grid elements 320 belonging to the group 350. Such an area is exemplary in Fig. 6 , shown below. In the case that this area is monochrome, its color corresponds to the group color 360. If the area comprises several colors or a color gradient, the group color 360 is formed as a mean or mode value over the colors of the area.

In Fig. 7 It is indicated how, depending on the group color 360 for the raster elements 320 of the group 350, locally, ie only for the one group 350 and only dependent on the group color 360 determined for the one area, a sub-color space 370 is determined which comprises those colors then used to color the raster elements 320 of the group 350, ie to encode the information unit 301 in the area in which the elements 320 of the group 350 are arranged. The size of this sub-color space 370, ie the number of different colors in this sub-color space, can be predetermined and specified, for example, for decoding, in the header information 332. In the example shown, sub-color space 370 includes four colors 372, 374, 376, and 378.

The colors 372, 374, 376, 378 of the sub-color space 370 differ from the group color 360 only in one color parameter, in the example shown in the brightness. Other color parameters, for example saturation or tone value, or predetermined combinations of such color parameters can also be used to form the colors of the sub-color space in a predefined manner, starting from the group color. The colors of the sub-color space are thus formed or calculated so that they are always similar to the group color, and thus similar to the color of the area of the information unit in which the elements of the grid colored by these colors are then arranged as part of the encoding. In this way it can be ensured that the color space of the coding and thus the adaptive raster in each area of the information unit is adapted to the color space of the information unit.

In Fig. 8 shows exemplarily how a decoding of a coding introduced by means of the colors 372, 374, 376, 378 of the sub-color space 370 in the corresponding area of the information unit can be decoded in a simple manner. For this purpose, two particular colors 372, 378 of the sub-color space 370 are selected as first and second reference colors, namely, those colors of the sub-color space 370 that most clearly differ with respect to the predetermined color parameter within the sub-color space 370. In the example shown, these are the brightest 372 and darkest color 378 of the sub-color space 370. These two reference colors color two predetermined elements of the group 350, namely the element 381 in the upper left corner and the element 382 in the lower left corner of the 2 * 2- Partial grid forming the group 350. This procedure serves to capture the colors of these two predefined elements in the step of decoding and to evaluate them as reference colors 372, 378. Based on these reference colors 372, 378, and knowing the number of colors of the sub-color space 370, then the remaining colors 374, 376 of the sub-color space 370 can be locally determined uniquely.

As in FIG. 9 Left side indicated, each color 372, 374, 376, 378 of the sub-color space 370 can be uniquely assigned a character string which can be coded by means of this color. The two other raster elements 383, 384 of the group 350 can, as in Fig. 9 , right side, indicated, are now freely used to encode information, ie colored by one of the colors 372, 374, 376, 378 of the sub-color space 370, respectively.

In Fig. 10 finally, an information unit 301 completely encoded in the manner described above is shown by way of example. For the sake of clarity, all the groups 350 have been colored here with respect to the same group color 360, as would be the case, for example, if the information unit 301 as a whole were monochrome.

In Fig. 11 is a variant 401 of the coded information unit 301 from Fig. 10 shown. This is different from the one Fig. 10 in the manner of the position markings 430, 440. In the in Fig. 11 The position marks 430, 440 comprise a plurality of raster elements 320, corresponding to the previously described groups 350 of contiguous raster elements 320. The position markings 430, 440 are once on it to recognize that individual of the raster elements of the position marks 430, 440 are colored by means of a specific marking color 361. The marker color 361 is characterized in that it does not exceed a predetermined color difference to a color of the area in which the raster elements of the position marker are arranged. In other words, the highlight color 361 is similar to the corresponding color of the area of the information unit. Alternatively, a plurality of marking inks could be used, which then each satisfy the color difference criterion specified above. In principle, it is possible to determine a marker color 361 as in determining the group color for a group of raster elements or as in determining the colors of a sub-color space for such a group. In the example shown, the one marking color 361 corresponds to the group color 360, ie the color difference of the marking color 360 to the color of the corresponding area of the information unit is zero. However, the marking color 361 may also differ within predetermined limits from the color of the corresponding area of the information unit as long as no confusion with a color of a corresponding partial color space of a group of raster elements potentially associated with this area is to be feared.

Another characteristic of the markers 430, 440 is the specific spatial arrangement of a plurality of raster elements colored in the marker color 361 to each other - diagonally opposite in the position markings 430, in L-shape in the position marks 440. It may be used in connection with such an embodiment instead a marking color 361 also different marking colors are used.

As in Fig. 11 , especially compared to Fig. 10 , can be obtained by means of appropriately formed position marks 430, 440 a visually very inconspicuous coding of the information unit 301 can be obtained. However, the cost of decoding, recognizing and evaluating the location marks 430, 440, increases as compared to the use of conventional location markers, as in FIG Fig. 10 , This is essentially because the adaptive raster as such in one embodiment Fig. 11 must be detected in a first sub-step of the decoding without the aid of position marks 430, 440. In this respect, the bearing marks 440, which are provided for determining the boundaries of an information-coding area of the information unit, in the context of an in Fig. 11 illustrated embodiment basically omitted, since the grid and its limits can be detected without these marks.

Claims (15)

Method for coding information into a graphic information unit (1), characterized by the steps: - Determining an outer contour (2) of the information unit (1); and - Coding information by means of at least two-dimensional code (10) in at least one area (3) exclusively within the outer contour (2), wherein the coding on pixels (11 a, 11 b) of the information unit (1) is applied. The method of claim 1, wherein a three-dimensional color coding is used, wherein a color space of the color code is at least a part of a color space of the information unit (1). A method according to claim 1 or 2, wherein an adaptive grid is used for the coding, which is adapted to the outer contour (2) and / or the color space of the information unit (1). A method according to claim 2 and 3, wherein an element of the adaptive raster is assigned a color of the color space of the color code based on a color difference between that color and a color of the information unit (1) at the position corresponding to the element of the adaptive raster. The method of claim 2 and 3, wherein a sub-color space (370) of the color code for a group (350) of elements (320) of the adaptive raster is determined locally, depending on a group color (360) corresponding to an area of the information unit (301). it is determined in which the group of elements of the adaptive grid is arranged. The method of claim 5, wherein each of the colors (372, 374, 376, 378) of the sub-color space (370) is different from the group color (360) with respect to a given color parameter. The method of claim 6, wherein - a given element of the group of elements of the adaptive grid is colored with that color of the sub-color space that differs most clearly from the group color with respect to the given color parameter, or wherein the two colors (372, 378) of the sub-color space (370) are selected which differ most clearly from one another with respect to the predetermined color parameter, and wherein a first predetermined element (381) of the group (350) of elements of the adaptive raster with the first (372) of the two colors is colored and a second predetermined element (382) of the group (350) of elements of the adaptive grid is colored with the second (378) of the two colors. Method according to one of claims 1 to 7, wherein the coding has at least two markers for a position detection of the information unit (5). The method of claim 8, wherein a three-dimensional color coding is used and wherein for the coding an adaptive grid is used, which is adapted to the outer contour and the color space of the information unit (1), and wherein markers for the position detection by coloring at least one element of the adaptive Raster is formed with at least one marking color, wherein the at least one marking color does not exceed a predetermined color difference to a color of a portion of the information unit in which the at least one element is arranged. The method of claim 9, wherein a mark for location detection is formed by coloring a plurality of elements of the adaptive grid with at least one of the at least one highlight color, wherein the elements of the plurality of elements with respect to the adaptive grid having a predetermined positional relationship to each other. Method according to one of the preceding claims, wherein the coding has a header with information about the coding. Method according to one of the preceding claims, wherein the information is encoded in the coding. Method for decoding information from a coded graphic information unit (5), characterized by the steps: - Detecting a coded by a method according to at least one of claims 1 to 12 information unit (5); and - decoding the information from the coded information unit (5). The method of claim 13, wherein a detection device (6, 7, 8) transmits the information to a database and obtains further information associated with the information from the database, or wherein the detection device (6, 7, 8) processes the information. Method according to one of claims 13 or 14, wherein in the decoding at least one of the following steps is carried out: - adapting and / or applying a raster to the acquired coded information unit (5); - Detecting an orientation of the detected coded information unit (5) based on at least two markers; - Capture a header; Decoding the information based on indications of the header; - performing an error correction; - decrypt the information; - Display the information.

Images